Multiresidue Method For The Determination Of Triazine Herbicides In Grains

Triazine compounds are employed as pre- and post-emergence herbicides to control many grass and broad-leaf weed in crops and non-agricultural land, especially in maize field where atrazine is most often used. They can exist for many moths in the crops and soils. In addition, The properties of low polarity and certain water solubility make these compounds easy to spread rapidly with the flow of surface-water and leads to environmental contamination and then do harm to human health. In the past, the determination methods of triazines mostly focused on environmental water, soil, fruits, vegetable and seldom on grain.A new gas chromatographic multi-residue method was developped to determine 21 triazine herbicides using chromatography-nitrogen phosphorus detector, which include most triazines such as simeton, simazine, atrazine, propazine, terbumeton, terbuthylazine, cyprazine, simetryn, prometryn, terbutryn, methoprotryne and hexazinone. A DB-5 capillary column was used for the temperature-programmed chromatographic simultaneous determination of these herbicides. Sample was extracted by acetonitrile, then cleaned up on a SCX SPE column. Without liquid-liduid partition procedure, both organic solvent and operation time were saved. SCX cartridge can completely separate triazines from co-extractives. As solvent passing through the tube by gravity, the cleanup procedure was easily carried out without other special equipment.Moreover, another method to determine triazines by GC-MSD was described. The method was optimized with higher sensitivity by operating in slected ion monitoring mode. Some disturbance can also be eliminated in SIM mode.Triazines were identified by comparing retention times to standard solutions and quantified with internal standard method. Diazinon was choosen as internal standard in both methods. Average recoveries and the relative standard deviations of samples fortified at 0.01-0.5mg/Kg levels were satisfying. The limits of quantitation of the methods were 0.01mg/Kg. They can be applied to determine triazines not only in grains such as maize, wheat, durra, barly and rice but also samples containing more oil and fat such as soy. Furthermore, the two methods showed good reproducibility, high sensitivity and comprehensive application prospect.